There are many well known types of far infrared imaging systems which are described in detail in texts such as The Detection and Measurement of Infrared Radiation, by R. A. Smith et al. The instant invention differs from these by using a unique, two step, thermo-optical imaging process. Several systems have been proposed using a thermal-to-optical transducer; however, in these the transducer was required to convert from the far infrared to the visible and to provide sufficient contrast for direct visual observation. In the instant invention, the transducer is only required to make the far infrared-to-optical conversion, with the contrast enhancement provided by the ac-coupled optical amplifier. Relaxation of the output contrast requirements of the transducer dramatically improves the resolution, time response, and thermal sensitivity of the system. The advantages of this approach over previous methods are discussed in my article entitled Advanced FLIR Concepts presented at the IRIS Imaging Specialty Group Meeting at El Toro Marine Base, California, in Feb. of 1977 and published in the IRIS proceedings.